Preparation Of Silver Based Functional Materials And Study Performance Of Water Disinfection

Nowadays,environment and energy issues are very serious in the world,which have attracted people's attention.Among them,microbial contamination has always been threatening the health of human beings.Many kinds of bacteria such as E.coli and S.aureus can result in seriously and even deadly infections for people.Therefore,it is urgently to develop effective and low-cost disinfecting technologies to address the problems of microbial contamination that human is facing.In 1985,Tadashi Matsunaga etc.was first reported the disinfection method of TiO₂,photocatalytic disinfection has since draw extensively investigated.Photocatalytic materials can produce h⁺?e^-and·O₂^-under visible light irradiation which can inactivate bacteria.This method is regarded as a green and energy-saving disinfection technology due to it uses the abundant solar energy.Ag₂WO₄/g-C₃N₄ composite photocatalyst was synthesized by polymerization of thiourea and ammonia chloride combined with the deposition-precipitation method,which was applied as an efficient visible-light driven photocatalyst for inactivating E.coli.The physicochemical properties of these photocatalysts were systematically characterized by various techniques such as SEM,TEM,XRD,FT-IR,BET,UV-Vis DRS and PL.The optimal mass ratio of the Ag₂WO₄ to g-C₃N₄ was 5 wt%,and a number of live bacteria could be completely inactivated with Ag₂WO₄?5%?/g-C₃N₄?100?g/mL?after 90 min under visible light irradiation.The high disinfection efficiency is due to the synergetic effect between g-C₃N₄ and Ag₂WO₄,including a good distribution of Ag₂WO₄ particles on the surface of g-C₃N₄ and an improved separation rate of photogenerated electron-hole pairs.The enhanced disinfection mechanism was also investigated using photogenerated current densities and electrochemical impedance spectroscopy?EIS?.Considering the bulk availability and excellent disinfection activity of Ag₂WO₄/g-C₃N₄ composite,it is a promising solar-driven photocatalyst for cleaning the microbial contaminated water.Ag₂O/BiOBr composite photocatalysts synthesized by in situ loading Ag₂O nanoparticles on BiOBr sheets,was used as an efficient visible-light-driven photocatalyst for the inactivation of E.coli.The Ag₂O/BiOBr composites exhibited significantly enhanced photocatalytic activity for the disinfection of E.coli under visible light irradiation.Photoluminescence spectra,and photo-electrochemical methods including transient photocurrent response,electrochemical impedance spectroscopy?EIS?spectra indicated the high photoinduced charge separation efficiency possess in Ag₂O/BiOBr composites.Active species trapping experiments by employing chemical scavengers confirmed that h⁺and e^-were the main active groups during the disinfection process.Through the combination of various performance characterization and experimental results,a possible disinfection mechanism was proposed.Some active species such as·OH,h⁺,and·O₂^-produced in photocatalytic disinfection process eventually result in the death of E.coli.Considering the excellent disinfection activity of Ag₂O/BiOBr,this work could provide a promising candidate in the actual contaminated natural waters for cleaning microbial.